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At least 1,441 records · Page 80Linked to original sources
PubMed1991

Computed tomography-guided minithoracotomy for the resection of small peripheral pulmonary nodules.

Small peripheral pulmonary nodules ranging in size from 1 mm to 20 mm were excised in 58 patients. Computed tomography was used to mark the skin overlying the nodules to minimize the surgical exposure needed for operative identification. The nodules were 1 cm or less in maximum diameter in 76% of the patients. Twenty-six patients had single nodules and 32 patients had multiple nodules. The preoperative diagnosis was inaccurate in 67% of the patients. In 61% of the patients in whom malignancy was suspected, no tumor was demonstrated. Conversely, of the 20 patients in whom a malignant nodule was excised, the preoperative diagnosis was correct in only 50%. Thirty-one patients required no further treatment apart from their biopsy and 27 required additional intervention. Small peripheral pulmonary nodules require biopsy for diagnosis. When percutaneous needle aspiration biopsy is unsuccessful, or technically difficult, a computed tomography-guided thoracotomy is an effective and minimally invasive surgical alternative.

Adult↗
PubMed1979

[Computer tomography in the diagnosis of aortic aneurysms (author's transl)].

The paper describes the diagnosis of ten thoracic, 20 abdominal and three peripheral arterial aneurysms by computer tomography. This permits a definite diagnosis by a non-invasive method, it defines the extent of the aneurysm and the amount of thrombus in the aneurysm; it permits recognition of a leak and is painless and without risk and can be performed rapidly. Morever, computer tomography provides an accurate control of growth of the aneurysm. In some cases a dissection can be recognised. The use of adequate quantities of intravenous contrast medium prevents any possibility of an incorrect diagnosis. The extent and density of the aneurysms, their lumina, clot and wall thickness, as determined by computer tomography are described. The values are compared with the aortic diameters of patients with normal vessels. The advantages of the method, compared with other procedures, are discussed and its role in the diagnosis of aortic and peripheral arterial aneurysms is described.

Aged↗
PubMed2002

Automated and representative fascicle selection for computer-assisted morphometry of myelinated nerve fibres in peripheral nerves.

We describe an algorithm that permits representative fascicle selection for sample acquisition from the entire cross-section of a nerve. We calculate the number of fascicles necessary for the acquisition of a given sample volume of nerve fibres from the image magnification, determine the scheme of intrafascicular sampling, and measure the (estimated) nerve fibre density. We start by storing the positions of all fascicles as coordinates of the microscope motor stage. We then recruit the needed fascicles from the file by calling them up out of the storage order with a constant interval, using the quotient of the total number of fascicles and the number of fascicles necessary to obtain the sample size for this purpose. The results obtained on the analysis of 40 specimens of sural and tibial nerves by means of the image analysis system IBAS are reported.

Algorithms↗
PubMed1981

[A thermodynamic model to predict oxygen consumption and peripheral blood flow of the newborn infant (author's transl)].

The continuous evaluation of the oxygen consumption and peripheral blood flow is technically difficult and practically not feasible in the newborn infant. We attempted to assess these two variables by means of a thermodynamic model, where only a set of geometrical variables and a set of temperatures have to be measured. The body is represented by a central cylinder (head, trunk) and a peripheral cylinder (extremities) and the heat flux therein is described by mathematical formulas. Only steady state conditions are considered. From the heat flux "surface leads to environment" the oxygen consumption and from the heat flux "central cylinder leads to peripheral cylinder" the peripheral blood flow is derived. On the patient only one core temperature (rectum) and two skin temperatures--one on the chest and the other one on the calf--have to be measured. The validity of the model was tested in 17 healthy newborns (body weight 1,100-3,850 g) and 6 diseased newborns (body weight 1,500-3,400 g). Comparing the computed oxygen consumption to values from the literature for a similar group showed good agreement. In 7 newborns the calculated oxygen consumption correlated well (r = 0.88, p less than 0.01) with the directly and synchroneously measured oxygen consumption. Indirect proof that the model also gives a reasonable index for the peripheral blood flow was obtained by relating the computed peripheral blood flow a) to values from the literature for a similar group and b) by demonstrating the dependence of the (calculated) peripheral blood flow on the haematocrit (r = -0.58, p less than 0.01).

Humans↗
PubMed1993

Air bronchogram in differential diagnosis of small peripheral lung cancers on CT image.

The computed tomographic (CT) images of 52 patients of small peripheral lung nodule < 3 cm proved pathologically were reviewed. Air bronchogram (AB) was found in 14 nodules on thin-section CT images, in which well or moderately differentiated small adenocarcinomas were only seen with lipidic growth. Squamous-cell, large-cell carcinomas and small benign lung nodules had no AB sign both on CT image and in pathologic specimens.

Adenocarcinoma↗
PubMed1980

Comparison of vertebral and peripheral mineral losses in disuse osteoporosis in monkeys.

Vertebral mineral loss (measured by computed tomography) was compared to peripheral mineral loss (measured by photon absorptiometry) in immobilized monkeys. Significantly greater loss was found in axial cancallous bone than in peripheral cortical bone. The accuracy of vertebral CT measurements in one animal was determined using direct chemical analysis of excised vertebrae. Results indicate that mineral changes may be detected earlier in the vertebrae by CT than in peripheral bone using photon absorptiometric techniques.

Absorption↗
PubMed1997

Pictorial review: imaging of peripheral nerve tumours.

The ultrasound, computed tomography and magnetic resonance features of extracranial nerve tumours are reviewed. Characteristic locations and appearances help to define nerve tumours although the imaging findings of nerve and other soft tissue tumours overlap.

Amputation Stumps↗
PubMedDate not supplied

Myxoid intraneural cysts of external popliteal ischiadic nerve. Report of 2 cases studied with ultrasound, computed tomography and magnetic resonance imaging.

Peripheral neuropathy of the external popliteal ischiadic nerve caused by intraneural cysts is a very rare and peculiar pathological phenomenon compared with diseases associated with extraneural cysts or colliquative phenomena of solid nervous lesions. Two cases of peripheral neuropathy of the external popliteal ischiadic nerve caused by intraneural cysts and evaluated with ultrasound, computed tomography and magnetic resonance are described. The diagnostic efficacy of these imaging modalities is also evaluated with particular reference to MR capability to define the morphology of such lesions and their relationships to the surrounding structures. It is not yet possible to obtain a correct diagnosis about histopathologic features by means of the imaging techniques currently available. Nevertheless, they do provide information about the involvement of the neighboring areas, which are useful indications for possible surgical treatment of the disease.

Adult↗
PubMed1986

[Diagnostic imaging of peripheral soft tissue tumors with special reference to computed tomography].

The further development of modern therapeutical procedures in the treatment of soft tissue tumors requires an improvement of radiological diagnostics. The diagnostic values of X-rays, angiography, sonography and computed tomography is estimated critically. The results of own CT examinations in 120 patients with soft tissue tumors and of 50 ultrasound examinations show the importance of these methods in the extent diagnosis of soft tissue tumors. Ultrasound or CT- guided biopsy are helpful to prove the definitive diagnosis. These methods have reduced the use of angiography.

Adolescent↗
PubMed1990

Magnetic resonance imaging simulator: a teaching tool for radiology.

The increasing use of magnetic resonance imaging (MRI) as a clinical modality has put an enormous burden on medical institutions to cost effectively teach MRI scanning techniques to technologists and physicians. Since MRI scanner time is a scarce resource, it would be ideal if the teaching could be effectively performed off-line. In order to meet this goal, the radiology Department at the University of Pennsylvania has designed and developed a Magnetic Resonance Imaging Simulator. The simulator in its current implementation mimics the General Electric Signa (General Electric Magnetic Resonance Imaging System, Milwaukee, WI) scanner's user interface for image acquisition. The design is general enough to be applied to other MRI scanners. One unique feature of the simulator is its incorporation of an image-synthesis module that permits the user to derive images for any arbitrary combination of pulsing parameters for spin-echo, gradient-echo, and inversion recovery pulse sequences. These images are computed in 5 seconds. The development platform chosen is a standard Apple Macintosh II (Apple Computer, Inc, Cupertino, CA) computer with no specialized hardware peripherals. The user interface is implemented in HyperCard (Apple Computer Inc, Cupertino, CA). All other software development including synthesis and display functions are implemented under the Macintosh Programmer's Workshop 'C' environment. The scan parameters, demographics, and images are tracked using an Oracle (Oracle Corp, Redwood Shores, CA) data base. Images are currently stored on magnetic disk but could be stored on optical media with minimal effort.

Computer Simulation↗
PubMedDate not supplied

Intraductal mucosal-spreading mucin-producing peripheral cholangiocarcinoma of the liver.

The computed tomographic (CT) appearance of a case of intraductal mucosal-spreading mucin-producing peripheral cholangiocarcinoma of the liver is described in a patient presenting with acute pericardial tamponade due to rupture of the cystically dilated left intrahepatic ducts by mucin hypersecretion. CT showed cystic and tubular dilatation of the intrahepatic ducts of the left and caudate lobes, but there was no grossly visible tumor mass. Pathology showed a single layer of tall columnar tumor cells with short intraluminal papillary projections lining each bile duct; the ducts were markedly dilated because of excessive mucin secretion. There was no gross tumor mass in the bile ducts. The tumor spread diffusely and contiguously along the intrahepatic bile ducts, with minimal invasion to the bile duct wall. To our knowledge, there has been no report about mucosal-spreading peripheral cholangiocarcinoma of the liver.

Bile Duct Neoplasms↗
PubMed1999

Influence of helical CT parameters on spatial resolution in CT angiography performed with a subsecond scanner.

RATIONALE AND OBJECTIVES: In helical CT, the beam collimation, table feed (TF) per tube rotation, voltage, current, reconstruction increment, kernel, linear interpolation algorithm (LIA), and contrast are variable parameters. The purpose of this study was to determine which of these parameters are most important to minimize partial volume effects for improving spatial resolution in CT angiography. METHODS: Phantom vessel stenoses of different lengths (2, 8 mm) and diameters (0.5, 1, 2, 3, 4 mm) were scanned with helical CT using a constant tube rotation time of 0.75 sec and 42 selected combinations of the above-mentioned parameters. Orthogonal targeted maximum intensity projections of the stenoses were ordered according to the increase in blurring and noise in a consensus reading by two radiologists blinded to the parameters used. RESULTS: Three millimeters of collimation and TF in conjunction with a 180 degrees LIA and > 250 Hounsfield unit contrast density was considered the optimal parameter combination and enabled a continuous visualization of the stenoses down to 0.5 mm in diameter. A collimation of 1 or 2 mm and 5 mm was considered inferior to a collimation of 3 mm because of, respectively, noise and blurring. With 3 mm collimation, significant blurring occurred when a pitch larger than 1.5 was used. A 3 mm collimation with a pitch of 2 (6 mm TF) was found to be superior to a collimation of 5 mm in conjunction with a pitch of 1 (5 mm TF). With 5 mm collimation, the short stenoses could be visualized only when using a 180 degrees LIA and a TF per tube rotation smaller than 7 mm. Eight and 10 mm collimations failed to depict the short stenoses. CONCLUSIONS: Collimation had the most influence on image quality in CT angiography, followed by LIA, pitch, and contrast density. Decreasing the reconstruction increment to less than one third of the TF or increasing the voltage or current beyond standard values did not improve the delineation of the stenoses. For screening examinations, the authors recommend the use of 3 mm collimation, 180 degrees LIA, and a pitch of 2.

Angiography↗
PubMed2001

[Fluoroscopy-assisted thoracoscopic surgery after computed tomography-guided bronchoscopic barium marking: a minimally invasive treatment for small peripheral early adenocarcinoma of the lung].

We developed a marking technique and subsequent thoracoscopic wedge resection as a diagnostic procedure for small peripheral lung nodule and a treatment for small peripheral early lung cancer. Fluoroscopy-assisted thoracoscopic surgery after computed tomography-guided bronchoscopic barium marking. Through CT-guided bronchoscopy, barium marking is done at just central to the target lesion. Thoracoscopic surgery is performed some days later. The barium marking was grasped in the forceps and resected by endostaplers under both intraoperative fluoroscopic and thoracoscopic guidance. All the lesions could be resected with enough surgical margin. This minimally invasive surgery is indicated for small peripheral in situ adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed1996

Interactive influences of ethnicity, gender and parental hypertension on hemodynamic responses to behavioral challenge.

To determine the independent and interactive influences of ethnicity, gender and parental hypertension on the magnitude and patterning of hemodynamic responses to standardized laboratory stressors, 112 normotensive, young adult African-American and Caucasian subjects (56 women, 56 men) completed a four-task protocol: three psychological stressors (the Stroop Color Word task, mental arithmetic and mirror tracing) and the forehead cold pressor test. Blood pressure (BP), heart rate (HR) and impedance derived measures of cardiac pre-ejection period and stroke volume were measured at rest and during each task; calculated indices of cardiac output and total peripheral resistance were also computed. Women responded to the psychological stressors with significantly larger increases in HR and cardiac output, less change in total peripheral resistance and greater attenuation of cardiac pre-ejection period than did men; however, blood pressure responses did not vary by gender, ethnicity or parental history of hypertension. Across tasks, African Americans showed larger elevations in total peripheral resistance than did Caucasians; conversely Caucasian subjects showed a more pronounced cardiac responsivity to stress, as evidenced by an elevated cardiac output and concomitant decrease in cardiac pre-ejection period, compared to their African-American counterparts. The ethnic differences in reactivity to psychological stressors were more apparent among males, while the gender differences were generally more pronounced among African Americans. Finally, the cold pressor test elicited larger increases in systolic blood pressure (SBP) among Caucasian subjects with family history positive (FH+), relative to family history negative (FH-) subjects, and also caused a greater reduction in HR among males compared to females.

Adult↗
PubMed2002

Computed tomographic image comparison between mediastinal and lung windows provides possible prognostic information in patients with small peripheral lung adenocarcinoma.

OBJECTIVES: The purpose of this study was to determine whether the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image can be a prognostic factor of small peripheral lung adenocarcinoma. METHODS: We studied the computed tomographic images of 143 patients with primary peripheral lung adenocarcinoma of 30 mm or less in maximum diameter. Two groups were categorized according to the tumor's ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image (tumor's area in the mediastinal computed tomographic image/tumor's area in lung computed tomographic image x 100%), both faint density-type (<50%) and solid-type images (>/=50%). Clinical factors and prognoses of the 2 groups were analyzed. RESULTS: There were 58 patients with the solid-type tumor image and 85 patients with the faint density-type tumor image. The number of patients with tumor size of less than 20 mm in the faint density-type tumor group (n = 30) was significantly higher than that in the solid-type tumor group (n = 8, P =.008). The 5-year survival of patients with faint density-type tumors was 74.1%, whereas that in patients with solid-type tumors was 54.2% (P =.013). Furthermore, the survival curve of patients with the solid-type computed tomographic image combined with ground-glass opacity was similar to that of patients with the faint density-type image. Multivariate analysis revealed the prognostic influence of the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image on survival (P =.029, relative risk = 0.48) and showed to be of second highest influence after the N factor. CONCLUSIONS: It is suggested that the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image can be a prognostic factor in patients with small peripheral lung adenocarcinoma.

Adenocarcinoma↗